Retention mechanism for high mass add-in cards

ABSTRACT

An electronic system includes a system board, a connector mounted on the system board, an electronic card attached to the connector, the card overhanging the connector at least on an inward end of the card, and a guide secured to the system board and spaced from the connector, wherein the guide is adapted to inhibit lateral movement of the card.

[0001] The invention relates to electronic systems, and moreparticularly to novel connectors and retention mechanisms for add-incards.

BACKGROUND AND RELATED ART

[0002] Many electronic systems provide the capability to supplement thefunctionality of the system by providing an interface through whichadditional electronic circuitry can be added to the system. For example,with reference to FIG. 1, a typical computer system 10 provides severalconnector slots 11 which are adapted to accept add-in cards 12. Theadd-in cards 12 may be retained by the mechanical forces between theconnector 11 on the system board 13 and the card edge connector 14 onthe add-in card 12. In many cases a bracket 15 is provided on the add-incard 14 which is secured to the chassis of the system at one end with ascrew.

[0003] Some memory devices, which are relatively small, include latcheson both ends of the memory connector. The latches help retain the memorycard in the slot and may also be used to eject the memory card.

[0004] The power consumption and complexity of computer add-in cards hasbeen increasing due to performance demands. For example, conventionalhigh performance video cards may require power of about 25 watts and mayweigh about 300 grams. As the required power increases, the weight ofthe add-in card consequently increases due to the need for more complexthermal solutions including larger heat sinks and fans. Even withoutincreased power demands, the mass of the add-in card may increase due tolarger card size and more devices and/or components on the add-in card.

[0005] If an add-in card is not sufficiently retained, the card can bedisplaced, or even popped off from the system board connector, e.g. dueto shock and vibration, resulting in an open circuit, or even structuredamage. The severity of the problem mainly depends on the card mass, thelocation of the center of gravity, and the card and connector design.Heavier add-in cards have more inertia during shock and/or vibrationevents. The increased card inertia applies a larger impact force onconstraining parts of the card such as the card connector, thuspotentially causing failures such as the connector housing pulling offfrom soldered pins and/or other damage on the connector housing itself.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Various features of the invention will be apparent from thefollowing description of preferred embodiments as illustrated in theaccompanying drawings, in which like reference numerals generally referto the same parts throughout the drawings. The drawings are notnecessarily to scale, the emphasis instead being placed uponillustrating the principles of the invention.

[0007]FIG. 1 is a perspective view of a conventional electronic system.

[0008]FIG. 2 is a schematic view of a conventional system subject to alateral force.

[0009]FIG. 3 is a top, schematic view of an electronic system accordingto some embodiments of the invention.

[0010]FIG. 4 is a side, schematic view of the electronic system of FIG.3.

[0011]FIG. 5 is a schematic view of another electronic system accordingto some embodiments of the invention.

[0012]FIG. 6 is a schematic view of another electronic system accordingto some embodiments of the invention.

[0013]FIG. 7 is a perspective view of a retention mechanism according tosome embodiments of the invention.

[0014]FIG. 8 is a fragmented, perspective view of an electronic systemincluding the retention mechanism of FIG. 7.

[0015]FIG. 9 is another perspective view of the retention mechanism ofFIG. 7 from a reverse angle.

[0016]FIG. 10 is a fragmented, perspective view of an electronic systemincluding the retention mechanism of FIG. 7 from the reverse angle.

[0017]FIG. 11 is a perspective view of another retention mechanismaccording to some embodiments of the invention.

[0018]FIG. 12 is another perspective view of the retention mechanism ofFIG. 11 from another angle.

[0019]FIG. 13 is an exploded perspective view of an electronic systemincluding the retention mechanism of FIG. 11.

[0020]FIG. 14 is an enlarged view of a mounting hole suitable for usewith some embodiments of the invention.

[0021]FIG. 15 is a perspective view of another retention mechanismaccording to some embodiments of the invention.

[0022]FIG. 16 is an exploded, perspective view of the retentionmechanism of FIG. 15.

[0023]FIG. 17 is another exploded, perspective view of the retentionmechanism of FIG. 15 from another angle.

[0024]FIG. 18 is a fragmented, perspective view of an electronic systemincluding the retention mechanism of FIG. 15.

[0025]FIG. 19 is a perspective view of another retention mechanismaccording to some embodiments of the invention.

[0026]FIG. 20 is a fragmented, perspective view of an electronic systemincluding the retention mechanism of FIG. 19.

[0027]FIG. 21 is a perspective view of an electronic system including aconnector with an integral retention mechanism according to someembodiments of the invention.

[0028]FIG. 22 is another perspective view of the electronic system ofFIG. 21 from a reverse angle.

[0029]FIG. 23 is a schematic view of mounting pins according to someembodiments of the invention.

[0030]FIG. 24 is a schematic view of other mounting pins according tosome embodiments of the invention.

[0031]FIG. 25 is a perspective view of a stiffening bracket according tosome embodiments of the invention.

[0032]FIG. 26 is a fragmented, perspective view of an electronic systemincluding a stiffening bracket according to some embodiments of theinvention.

[0033]FIG. 27 is a fragmented, perspective view of another electronicsystem including a stiffening bracket according to some embodiments ofthe invention.

DESCRIPTION

[0034] In the following description, for purposes of explanation and notlimitation, specific details are set forth such as particularstructures, architectures, interfaces, techniques, etc. in order toprovide a thorough understanding of the various aspects of theinvention. However, it will be apparent to those skilled in the arthaving the benefit of the present disclosure that the various aspects ofthe invention may be practiced in other examples that depart from thesespecific details. In certain instances, descriptions of well knowndevices, circuits, and methods are omitted so as not to obscure thedescription of the present invention with unnecessary detail.

[0035] As noted above, conventional high performance graphics cards mayweigh about 300 grams. An add-in graphics card supporting the AGPstandard may include a tab near the end of the connector to aid inretention of the card when the card is subject to vertical displacementforces. One problem with this tab is that to remove the card, theretention mechanism which engages with the tab must be manuallydisengaged. A further problem is that the supplemented retention isprimarily in the vertical direction.

[0036] The inventors have discovered that with heavier add-in cards(e.g. 350 grams or more), lateral forces on the card can unseat the cardand/or cause damage to the system. For example, lateral forces (i.e.forces including a component which is transverse to the plane of theadd-in card) may be generated when the electronic system is subject toan impact which is perpendicular to the orientation of the add-in card.With reference to FIG. 2, an electronic system 20 includes a systemboard 21 with a connector 22 mounted on the system board 21. An add-incard 23 is attached to the connector 22 and overhangs the connector 22on both ends. The add-in card 23 may include a bracket 24 on one endwhich may be attached to a chassis of the system 20. When a lateralforce F is applied to the card 23, an end 25 of the card (opposite ofthe bracketed end) may flex, as indicated by the curved arrows A and B.Under lateral forces, a point P near the end of the connector 22essentially becomes a pivot point about which the flexible material ofthe card 23 can bend. With a sufficiently heavy card subject to asufficiently heavy lateral force, the flexing end 25 of the card cantorque the card out of the connector and/or cause damage to the cardand/or system.

[0037] The inventors have performed extensive tests for heavier cards ina computer system to confirm that card retention failure during shockand vibration conditions may occur due to impacts made perpendicular tothe card. Even advanced graphics card with the additional retention tabfailed the tests. It is believed that the supplemental retention tab haslimited effect on restricting card deflection during side impact andtherefore is not satisfactory to solve the side impact failures. In someinstances (e.g. with a 400 gram graphics card), the additional retentiontab was broken during shock testing.

[0038] With reference to FIGS. 3 and 4, an electronic system 30according to some embodiments of the invention includes a system board31 and a connector 32 mounted on the system board 31. An electronic card33 is attached to the connector and overhangs the connector 32 (e.g. atleast on an inward end of the card 33 with respect to an outer wall ofthe system chassis). The system 30 further includes a guide 34 securedto the system board and spaced from the connector 32, where the guide 34is adapted to inhibit lateral movement of the card 33. For example, theguide 34 contacts one or more side surfaces of the card 33 to reduce theamount the card 33 may flex about the pivot point near the end of theconnector 32. Preferably, the guide 34 is adapted to provide a sideconstraint which substantially prevents lateral flexing of the card 33at the point where the guide 34 contacts the card 33.

[0039] As illustrated in FIGS. 3 and 4, the guide 34 contacts the card33 along a bottom edge of the card 33. Alternatively, a guide may beprovided that contacts the card in any location on the card which isfarther out from the pivot point. With reference to FIG. 5, a guide 54contacts the card 33 along a back edge of the card 33. With reference toFIG. 6, a guide 64 contacts the card 33 along both the bottom and backedges of the card 33, at a corner of the card 33. Although lesspreferred, suitable guides may be provided which contact the card alonga top edge or at some interior portion of the card. By providing a guidecontact point which is farther out than the pivot point, the pivot pointis moved to a location which allows less flexing and is therefore morelikely to successfully retain the card.

[0040] An appropriate guide for a particular electronic system may takeany suitable form and may be made from any suitable material. Plastic isa preferred material for the guide. Preferably, the guide provides aslot or channel that is a close fit with the thickness of the add-incard. For example, the guide may define a slot between two resilientprotrusions. The width of the slot may be less than the thickness of thecard, with the protrusions being sufficiently resilient to expand toaccept the card. An advantage of the resilient protrusions is that theyprovide retention forces in the both the vertical and lateraldirections, thus reducing the need for supplemental vertical retentionmechanisms like the retention tab found on some advanced graphics cards.The guide may include alignment features to aid in the positioning ofthe slot with respect to the connector.

[0041] With reference to FIGS. 7-10, an electronic system 80 includes asystem board 82 with a connector 84 mounted on the system board 82. Anadd-in card 86 is attached to the connector 84, with at least an inwardend of the card 86 overhanging the connector 84. A guide 88 is securedto the system board 82 and contacts the card 86 on both sides of thecard 86 at a point spaced from the connector 84. Accordingly, the guide88 inhibits lateral movement of the card 86.

[0042] In the example of FIGS. 7-10, the guide 88 defines an elongatedslot or rail 90 which extends from the end of the connector 84 forgreater than a majority of the length of the card overhang. The guide 88further includes two tabs 92 and 94 which extend vertically along thesides of the card 86 to raise the contact point. A higher contact pointprovides potentially greater stability. The tabs 92 and 94 are resilientand provide some inward bias to aid in retention of the card in thevertical direction. However, the card may be readily removed undermanual force. In other words, there is no positive locking mechanismthat must be disengaged before removing the card. This provides anadvantage over some card retention systems that provide verticalretention mechanism near the connector that must be disengaged beforethe card is released.

[0043] The guide 88 also includes two arms 96 and 98 as an alignmentfeature. The arms 96 and 98 are adapted to mate with an outer surface ofthe connector 84. Advantageously, the arms 96 and 98 provide correctpositioning of the rail 90 with respect to the connector 84.

[0044] To secure the guide 88 to the system board 82, the guide definesan opening 100 adapted to receive a fastener (e.g. a screw). The systemboard 82 provides a corresponding mounting hole (not shown). In someembodiments, the system board 82 corresponds to an ATX compatiblemotherboard. An advantage of the example of FIGS. 7-10 (and some otherembodiments) is that the guide 88 may be secured to an ATX mounting holealready provided on the motherboard, thus reducing the amount of reworkor board re-routing required to utilize the guide 88.

[0045] An unpackaged shock and vibration test was performed on anelectronic system utilizing the example guide 88 for retention of anadd-in card having a mass of about 450 grams. The center of gravity ofthe card was about 60 mm above the edge fingers and 100 mm from the cardbracket. The card was successfully retained and passed the shock andvibration test.

[0046] With reference to FIGS. 11-14, an electronic system 130 includesa system board 132 with a connector 134 mounted on the system board 132.An add-in card 136 is attached to the connector 134, with at least aninward end of the card 136 overhanging the connector 134. A guide 138 issecured to the system board 132 and contacts the card 136 on both sidesof the card 136 at a point spaced from the connector 134. Accordingly,the guide 138 inhibits lateral movement of the card 136.

[0047] As compared to the guide 88, the guide 138 occupies less boardspace. The guide 138 includes a keying feature 140 adapted to mate witha key-hole shaped mounting hole (see FIG. 14). For example, an ATXmounting hole may be modified into a key-hole shape. This keying featureallows a much smaller size for the retention rail, in comparison to theguide 88, which uses the connector for alignment.

[0048] With reference to FIGS. 15-18, an electronic system 150 includesa system board 152 with a connector 154 mounted on the system board 152.An add-in card 156 is attached to the connector 154, with at least aninward end of the card 156 overhanging the connector 154. A guide 158 issecured to the system board 152 and contacts the card 156 on both sidesof the card 156 at a point spaced from the connector 154. Accordingly,the guide 158 inhibits lateral movement of the card 156.

[0049] To further reduce the size of the guide 158, a push-pin mountstructure is shown in FIGS. 15-19. The guide 158 uses a side constraintto retain the card, but with only one push-pin to mount to the systemboard 152. For example, the guide 158 may be constructed from two pieces158A and 158B. The bottom piece 158A is inserted into a key-hole on thesystem board 152 and the top piece 158B with a push-pin 160 is theninserted into the bottom piece 158A, creating the mechanical pressure toattach the guide 158 to the system board 152. The keying features ensurecorrect alignment. This example has some advantages. First, it offersgreat flexibility. For example, a motherboard vendor does not have toinstall this guide in the first instance, giving a downstream systemmanufacturer the flexibility to install it on an as-needed basis.Second, it is extremely compact—the diameter of the guide may be only2-3 mm in diameter.

[0050] With reference to FIGS. 19-20, an electronic system 190 includesa system board 192 with a connector 194 mounted on the system board 192.An add-in card 196 is attached to the connector 194, with at least aninward end of the card 196 overhanging the connector 194. A guide 198 issecured to the system board 192 and contacts the card 196 on both sidesof the card 196 at a point spaced from the connector 194. Accordingly,the guide 198 inhibits lateral movement of the card 196.

[0051] The guide 198 defines a plurality (i.e. at least two) holes 200which are used as alignment features. Corresponding mounting holes areprovided on the system board. The mounting holes are configured suchthat when the holes 200 are aligned with the mounting holes, the slotdefined by the guide 198 is aligned with the connector 194. For example,the guide 198 may be mounted on the motherboard via two wave-solderedthrough-hole pins. Other methods of board mounting can also be used suchas press-fit, or the addition of snap-in features. Many variations ofthe guide 198 and mounting fasteners are possible. In one example, acut-out can be made for the guide 198 on the region between the twopins. The cut-out region can be used for IPAK components and routing onboard, thus reducing impact of the placement the guide 198 on boardlayout. The key advantages of this example are its flexibility,independence of form factors, and compactness.

[0052] With reference to FIGS. 21-24, a connector 210 includes anintegrated retention guide 212. Advantageously, the part count forassembly is reduced. In some embodiments, the length of the guide 212may be vertically extended. In some embodiments, the connector pinconnections to the motherboard may be strengthened by one of (or acombination of): widening of the base of the end of the connector;adding additional position pins 216; and/or using forklocks 218 for theposition pins; and/or utilizing wave solder pins 220 instead of plasticpins. The extension of the guide will increase the side constraintduring a shock event, reducing impact force on the connector. Thisreduced force, coupled with the strengthening of the connector pins isbelieved to reduce connector failures during shock and vibration.

[0053] With reference to FIGS. 25-26, an electronic system 250 includesa system board 252 with a connector 254 mounted on the system board 252.An add-in card 256 is attached to the connector 254. The add-in card 256includes a guide 258 disposed along a top edge of the card 256. Theguide 258 is adapted to inhibit lateral movement of the card 256. Forexample, the guide 258 provides stiffening to the add-in card 256. Thecard may be optionally secured to a bracket 260 attached to a front edgeof the card 256 or may be integrated with the bracket 260. For example,the guide 258 acts as a stiffening rib to the card 256 and reduceslateral deflection of the card 256 caused by an impact madeperpendicular to the card 256. Constrained side deflection reducesimpact force on the connector and thus reduces connector failures duringshock and vibration. Advantageously, because the guide 258 is disposedalong the top edge of the card 256, the guide 258 has no impact on thesystem board 252 layout or component placement.

[0054] In some embodiments, the guide 258 includes a flat strip 262which does not contact at least one side of the card 256. For example, acard may define a keep-out zone for the bracket 260. The guide 258 mayhave a middle section of a flat strip with no coverage on the cardsurface (see FIG. 26). Only a small additional keep-out zone may beneeded at the top end of the card opposite of the bracket end.

[0055] With reference to FIG. 27, an electronic system 270 includes asystem board 272 with a connector 274 mounted on the system board 272.An add-in card 276 is attached to the connector 274. The add-in card 276includes a guide 278 disposed along a top edge of the card 276. Theguide 278 is adapted to inhibit lateral movement of the card 276. Forexample, the guide 278 provides stiffening to the add-in card 276. Thecard may be optionally secured to a bracket attached to a front edge ofthe card 276 or may be integrated with the bracket. For example, theguide 278 acts as a stiffening rib to the card 276 and reduces lateraldeflection of the card 276 caused by an impact made perpendicular to thecard 276. Constrained side deflection reduces impact force on theconnector and thus reduces connector failures during shock andvibration. Advantageously, because the guide 278 is disposed along thetop edge of the card 276, the guide 278 has no impact on the systemboard 272 layout or component placement. In this example, the guidedefines a channel or rail which contacts both sides of the card 276along substantially the entire top edge of the card 276.

[0056] The foregoing and other aspects of the invention are achievedindividually and in combination. The invention should not be construedas requiring two or more of the such aspects unless expressly requiredby a particular claim. Moreover, while the invention has been describedin connection with what is presently considered to be the preferredexamples, it is to be understood that the invention is not limited tothe disclosed examples, but on the contrary, is intended to covervarious modifications and equivalent arrangements included within thespirit and the scope of the invention.

What is claimed is:
 1. An electronic system, comprising: a system board;a connector mounted on the system board; an electronic card attached tothe connector, the card overhanging the connector at least on an inwardend of the card; and a guide secured to the system board and spaced fromthe connector, wherein the guide is adapted to inhibit lateral movementof the card.
 2. The system of claim 1, wherein the guide is adapted toprovide a side constraint which substantially prevents lateral flexingof the card at a point where the guide contacts the card.
 3. The systemof claim 1, wherein the guide contacts one or more side surfaces of thecard.
 4. The system of claim 3, wherein the guide contacts two opposedside surfaces of the card.
 5. The system of claim 1, wherein the guideis positioned along a bottom edge of the card.
 6. The system of claim 1,wherein the guide is positioned along a back edge of the card.
 7. Thesystem of claim 1, wherein the guide is position along a top edge of thecard.
 8. The system of claim 1, wherein the guide is positioned at acorner of the card.
 9. The system of claim 1, wherein the guide includesan alignment feature adapted to align the guide with the connector. 10.The system of claim 9, wherein the alignment feature includes armsadapted to mate with the connector.
 11. The system of claim 9, whereinthe alignment feature includes a keying feature.
 12. A method,comprising: providing a system board; mounting a connector on the systemboard; attaching an electronic card to the connector, the cardoverhanging the connector at least on an inward end of the card; andsecuring a guide to the system board spaced from the connector; andinhibiting lateral movement of the card with the guide.
 13. The methodof claim 12, wherein inhibiting lateral movement of the card comprisesproviding a side constraint with the guide which substantially preventslateral flexing of the card at a point where the guide contacts thecard.
 14. The method of claim 12, wherein inhibiting lateral movement ofthe card comprises contacting one or more side surfaces of the card withthe guide.
 15. The method of claim 14, wherein the guide contacts twoopposed side surfaces of the card.
 16. The method of claim 12, whereinsecuring the guide comprises positioning the guide along a bottom edgeof the card.
 17. The method of claim 12, wherein securing the guidecomprises positioning the guide along a back edge of the card.
 18. Themethod of claim 12, wherein securing the guide comprises positioning theguide along a top edge of the card.
 19. The method of claim 12, whereinsecuring the guide comprises positioning the guide at a corner of thecard.
 20. The method of claim 12, further comprising providing the guidewith an alignment feature adapted to align the guide with the connector.21. The method of claim 20, wherein the alignment feature includes armsadapted to mate with the connector.
 22. The method of claim 20, whereinthe alignment feature includes a keying feature.